/Engine/Source/Developer/DirectoryWatcher/Public/IDirectoryWatcher.h
Register a callback to fire when directories are changed
bool RegisterDirectoryChangedCallback_Handle ( const [FString](API\Runtime\Core\Containers\FString) & Directory, const [FDirectoryChanged](API\Developer\DirectoryWatcher\IDirectoryWatcher\FDirectoryChanged) & InDelegate, [FDelegateHandle](API\Runtime\Core\Delegates\FDelegateHandle) & OutHandle, uint32 Flags )